Device and method for mitral valve regurgitation treatment

ABSTRACT

A mitral valve replacement device is adapted to be deployed at a mitral valve position in a human heart. The device has an atrial flange defining an atrial end of the device, a valve body defining a ventricular end of the device, and an annulus support that connects the atrial flange and the valve body, the annulus support including a ring of tabs extending radially therefrom and adapted to engage the native mitral annulus and/or the native leaflet(s) of the human heart. The atrial flange can be seated in the atrium above the native mitral valve annulus in a human heart, and the ring of tabs can engage the native mitral annulus in a manner where the atrial flange and tabs provide a clipping effect to secure the mitral valve replacement device at the native mitral valve position.

RELATED CASES

This application is related to Provisional Application No. 61/927,490,filed Jan. 15, 2014.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention generally relates to medical devices and methodsuseful for human mitral valve function repair and/or reconstruction. Inparticular, the present invention relates to a medical device that canbe used to treat mitral valve regurgitation by replacing the function ofnative heart valves.

2. Description of the Prior Art

The human heart has four chambers and four valves. The heart valvescontrol the direction of blood flow. Fully-functional heart valvesensure proper blood circulation is maintained during cardiac cycle.Heart valve regurgitation, or leakage, occurs when the leaflets of theheart valve fail to come fully into contact (coapt) due to disease, suchas congenital, torn chordae tendineae, lengthened chordae tendineae,enlarged left ventricle, damaged papillary muscles, damaged valvestructures by infections, degenerative processes, calcification of theleaflets, stretching of the annulus, increased distance between thepapillary muscles, etc. Regardless of the cause, the regurgitationinterferes with heart function since it allows blood to flow backthrough the valve in the wrong direction. Depending on the degree ofregurgitation, this backflow can become a self-destructive influence onnot only the function, but also on the cardiac geometry. Alternatively,abnormal cardiac geometry can also be a cause of regurgitation, and thetwo processes may “cooperate” to accelerate abnormal cardiac function.The direct consequence of the heart regurgitation is the reduction offorward cardiac output. Depending on the severity of the leakage, theeffectiveness of the heart to pump adequate blood flow into other partsof the body can be compromised.

The mitral valve is a dual-flap (bi-leaflet) valve in the heart thatlies between the left atrium (LA) and the left ventricle (LV). Duringdiastole, a normally-functioning mitral valve opens as a result ofincreased pressure from the left atrium as it fills with blood(preloading). As atrial pressure increases above that of the leftventricle, the mitral valve opens, facilitating the passive flow ofblood into the left ventricle. Diastole ends with atrial contraction,which ejects the remainder of blood that is transferred from the leftatrium to the left ventricle. The mitral valve closes at the end ofatrial contraction to prevent a reversal of blood flow from leftventricle to left atrium. The human mitral valve is typically 4-6 cm² inopening area. There are two leaflets, the anterior leaflet and posteriorleaflet, which cover the opening of the mitral valve. The opening of themitral valve is surrounded by a fibrous ring called the mitral valveannulus. The two leaflets are attached circumferentially to the mitralvalve annulus and can open and close by hinging from the annulus duringcardiac cycle. In a normally-functioning mitral valve, the leaflets areconnected to the papillary muscles in the left ventricle by chordaetendineae. When the left ventricle contracts, the intraventricularpressure forces the mitral valve to close, while chordae tendineae keepthe two leaflets coapting (to prevent two valve leaflets from prolapsinginto the left atrium and creating mitral regurgitation) and prevent thevalve from opening in the wrong direction (thereby preventing blood fromflowing back into the left atrium).

Currently, the standard heart valve regurgitation treatment optionsinclude surgical repair/treatment and endovascular clipping. Thestandard surgical repair or replacement procedure requires open-heartsurgery, use of cardio-pulmonary bypass, and stoppage of the heart.Because of the invasive nature of the surgical procedure, risks ofdeath, stroke, bleeding, respiratory problems, renal problems, and othercomplications are significant enough to exclude many patients fromsurgical treatment.

In recent years, endovascular clipping techniques have been developed byseveral device companies. In this approach, an implantable clip madefrom biocompatible materials is inserted into the heart valve betweenthe two leaflets to clip the middle portion of the two leaflets (mainlyA2 and P2 lealfets) together to prevent the prolapse of the leaflets.However, some shortcomings, such as difficulty of positioning,difficulty of removal once implanted incorrectly, recurrence of heartvalve regurgitation, the need for multiple clips in one procedure,strict patient selection, etc., have been uncovered in the practicalapplication of endovascular clipping.

In conclusion, there is a great need for developing a novel medicaldevice to treat mitral regurgitation. None of the existing medicaldevices to date address this need fully. The present invention aims toprovide physicians with a device and a method which can avoid atraumatic surgical procedure, and instead provide a medical device thatcan be implanted through a catheter-based, less invasive procedure formitral regurgitation treatment.

SUMMARY OF THE DISCLOSURE

It is an object of the present invention to provide a mitral valvereplacement device that can be effectively secured to the location ofthe human mitral valve annulus without the use of barbs or hooks thatpierce the native tissue.

It is another object of the present invention to provide a method ofdeploying a mitral valve replacement device at the location of the humanmitral valve annulus where the position of the device can be adjustedbefore deployment is completed.

It is yet another object of the present invention to provide a novelleaflet structure that provides more efficient valvular control andflow.

In order to accomplish the objects of the present invention, the presentinvention provides a mitral valve replacement device adapted to bedeployed at a mitral valve position in a human heart. The device has anatrial flange defining an atrial end of the device, a valve bodydefining a ventricular end of the device, and an annulus support thatconnects the atrial flange and the valve body, the annulus supportincluding a ring of tabs extending radially therefrom and adapted toengage the native mitral annulus and/or the native leaflet(s) of thehuman heart. The atrial flange has a diameter greater than the diameterof the valve body, and the annulus support has a diameter between thatof the diameter of the atrial flange and the diameter of the valve body.The atrial flange can be seated in the atrium above the native mitralvalve annulus in a human heart, and the ring of tabs can engage thenative mitral annulus and/or native leaflet(s) in a manner where theatrial flange and tabs provide a clipping effect to secure the mitralvalve replacement device at the native mitral valve position.

The present invention also provides a heart valve having a valve bodyand a leaflet structure attached to the valve body. The leafletstructure has three leaflets, each leaflet having radial edges and outeredges. Each outer edge of a leaflet is sewn to an outer edge of anadjacent leaflet along a longitudinal stitch line, and each radial edgeof a leaflet is sewn to a radial edge of an adjacent leaflet along aradial stitch line, with the radial stitch line along one of radialedges extending from the longitudinal stitch lines towards a centralpoint. The leaflet structure further includes three inner stitch linesthat originate from an apex that is offset from the central point, andwhich extend for a short distance towards the longitudinal stitch linesand merge with the longitudinal stitch lines, with the inner stitchlines forming an umbrella-shaped configuration for the combined threeleaflets. The leaflet structure can also have two or more than threeleaflets.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of a mitral valve device according to afirst embodiment of the present invention.

FIG. 2 is a bottom view of the device of FIG. 1.

FIG. 3 is a top view of the device of FIG. 1.

FIG. 4 is a side view of the device of FIG. 1.

FIG. 5A is another side view of the device of FIG. 1 which is rotated by90 degrees from the view of FIG. 4.

FIG. 5B illustrates the device of FIG. 1 positioned at the mitral valveannulus of a human heart.

FIG. 6A illustrates the two-dimensional flat configuration of the deviceof FIG. 1 after it has been laser cut from metal or polymer tubing.

FIG. 6B is a perspective three-dimensional view of the device laser-cutpattern shown in FIG. 6A, prior to forming the final shape as shown inFIG. 1. The device in its final shape can be integrated with the tissueleaflet(s) and skirt(s), can be compacted into a smaller profile, andloaded into a delivery system.

FIG. 7A is top view of an assembled mitral valve replacement device thatincludes the leaflets incorporated with the device of FIG. 1, with theleaflets in the opened position.

FIG. 7B is a bottom view of the assembled mitral valve replacementdevice of FIG. 7A with the leaflets in the opened position.

FIG. 8A is top view of an assembled mitral valve replacement device thatincludes the leaflets incorporated with the device of FIG. 1, with theleaflets in the closed position.

FIG. 8B is a bottom view of the assembled mitral valve replacementdevice of FIG. 8A with the leaflets in the closed position.

FIG. 9A is a perspective view of the leaflet assembly of FIG. 7A whenthe leaflets are opened, with the mitral valve closed.

FIG. 9B is a perspective view of the leaflet assembly of FIG. 7A whenthe leaflets are closed, with the mitral valve opened.

FIG. 10A is a top view of the leaflet assembly of FIG. 7A when theleaflets are opened, with the mitral valve closed.

FIG. 10B is a bottom view of the leaflet assembly of FIG. 7A when theleaflets are opened, with the mitral valve closed.

FIG. 11 is a top view of the leaflet assembly of FIG. 7A when theleaflets are closed, with the mitral valve opened.

FIG. 12 is a perspective view of a mitral valve device according to asecond embodiment of the present invention.

FIG. 13 is a side view of the device of FIG. 12.

FIG. 14 is another side view of the device of FIG. 12 which is rotatedby 90 degrees from the view of FIG. 13.

FIG. 15 illustrates the device of FIG. 12 positioned at the mitral valveannulus of a human heart.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

The following detailed description is of the best presently contemplatedmodes of carrying out the invention. This description is not to be takenin a limiting sense, but is made merely for the purpose of illustratinggeneral principles of embodiments of the invention. The scope of theinvention is best defined by the appended claims.

The subject technology relates generally to mitral regurgitationtreatment devices and to the manner of positioning and anchoring thedevice in a human heart. This device contains an atrial portion and aventricular portion. The atrial portion of the device “seats” at themitral annulus area to create a “seal” to prevent leakage (blood flowback from the left ventricle to the left atrium) from the areasurrounding the device. The ventricular portion of the device contains avalve body and anchoring features. The anchoring features can bepartially or fully covered by fabric or tissue to create a “seal” toprevent leakage. The valve body contains the tissue leaflet(s) andleaflet supporting structure. During normal cardiac cycle, the valve andleaflet(s) open and close to regulate the direction and volume of theblood flow between the left atrium and the left ventricle. The functionof the anchoring features is to maintain the proper position of thedevice to prevent potential migration during cardiac cycle. Theanchoring features provide an anchoring effect by interacting with thenative leaflet(s), and/or the annulus, and/or other subvalvularstructures. One design of the anchoring feature is to use biocompatibleadhesive/glue to form the bond between the device and the nativevalvular and/or heart structure to maintain the position of the valveprosthesis.

In use, the device will be delivered using a transcatheter approach tothe mitral space, and interact with the internal valvular structure andsubvalvular structures to restore the function of the mitral valve. Inaddition, this device can be implanted through surgical or otherminimally invasive procedures. The device can be implanted inside of aheart or a lumen in the human vasculature, which serves to improve,replace, and/or reconstruct the function of the native mitral leaflet(s)and mitral valve.

The present invention also covers an anchoring feature (clip design)that utilizes the native leaflet(s), and/or annulus, and/or othersub-annular structures to provide an anchoring effect to maintain thedevice in position during the cardiac cycle. Once the device is placedin the mitral position, the anchoring feature(s) on the deviceengage/interacts with the native leaflet(s), and/or annulus, and/orother subvalvular structures to prevent the device from migration duringcardiac cycle. The atrial portion of the device can also provide someadditional anchoring effect by interacting with the annulus and theatrial portion of the heart above the annulus that is in contact withthe atrial portion of the device.

The present invention also provides a novel leaflet design. The leafletconfiguration can contain one to six pieces of leaflets, which can besewn together inside the leaflet supporting structure to form anumbrella shaped profile that can open and close during the cardiac cycleto regulate the flow. During cardiac systole (heart contraction), theumbrella-shaped leaflets can open to a larger profile and to close themitral valve, so that there is no blood flow back to the left atriumfrom the left ventricle. During cardiac diastole (heart relaxation), theumbrella-shaped leaflets can close to a smaller profile and to open themitral valve, so that blood can flow from the left atrium to the leftventricle. The advantages of this novel valve leaflet design include:(i) no axial contraction/squeezing to the leaflet supporting structureby the leaflet(s) during the cardiac cycle, so as to improve the fatigueresistance of the supporting structure; (ii) better leaflet(s)coaptation, where the coaptation is between the leaflet(s) and theskirt(s) on the supporting structure, which minimizes the potential forcentral leakage, and (iii) there is no “free edge” at the centralportion of the leaflet(s). There is no coaptation between/among theleaflet(s). This feature is important because any deformation ordistortion of the valve supporting structure would result in minimalcentral leakage.

The mitral valve replacement device of the present invention can becompacted into a low profile and loaded onto a delivery system, and thendelivered to the target location by a non-invasive medical procedure,such as through the use of a delivery catheter through transapical, ortransfemoral, or transseptal procedures. The mitral valve replacementdevice can be released from the delivery system once it reaches thetarget implant site, and can expand to its normal (expanded) profileeither by inflation of a balloon (for a balloon expandable supportingstructure) or by elastic energy stored in the device (for a device witha self-expandable supporting structure).

The leaflet(s) in the mitral valve replacement device of the presentinvention can be made from treated animal tissue/pericardium, from thinwall biocompatible metallic element (such as stainless steel, Co—Crbased alloy, Nitinol, Ta, and Ti etc.), or from biocompatible polymermaterial (such as polyisoprene, polybutadiene and their co-polymers,neoprene and nitrile rubbers, polyurethane elastomers, silicone rubbers,fluoroelastomers and fluorosolicone rubbers, polyesters, and ptfe,etc.). The leaflets can also be provided with a drug or bioagent coatingto improve performance, prevent thrombus formation and promoteendotheliolization. The leaflet(s) on the mitral device can also betreated or be provided with a surface layer/coating to preventcalcification. The cover on the valve body and the leaflet supportingstructure can also be a combined layer from fabric and tissue, ifdesired. For example, the upper portion of the cover can be made fromfabric, while the lower portion can be made from tissue, or vice versa.The atrial portion of the device and the body of the leaflet supportingstructure can be either fully or partially covered by fabric or tissueto provide improved sealing effect and healing effect. The anchoringfeature(s) built on the device can be fully or partially covered byfabric or tissue to promote tissue growth, to prevent Perivalunaerleakage (PVL), and to reduce the potential damage to the surroundinginternal heart structure.

The leaflet(s) can be integrated into the leaflet supporting structureby mechanical interweaving, suture sewing, and chemical, physical, oradhesive bonding methods. The leaflet(s) can also be formed from theelements of the supporting structure. For example, the leafletsupporting structure and leaflet(s) can be directly molded and formedtogether from polymer or metal material. The leaflet(s) can also beformed by vapor deposition, sputtering, reflow, dipping, casting,extrusion processes or other mechanisms for attaching two or morematerials together.

The tissue leaflet(s) can also be coated with drug(s) or other bioagentsto prevent the formation of clots in the heart. Anti-calcificationmaterials can also be coated or provided on the surface to preventcalcification.

FIGS. 1-5 illustrate a first embodiment of a mitral valve device 20according to the present invention. The device 20 has an atrial flange22, an annulus support 24, a neck section 26 that connects the atrialflange 22 to the annulus support 24, and a valve body 28 that functionsas a leaflet supporting structure. Each of these components is definedby struts that define cells that in turn make up a cellular matrix.

The atrial flange 22, the annulus support 24 and the valve body 28 canbe made from either a Nitinol superelastic material or stainless steel,Co—Cr based alloy, Titanium and its alloys, and other balloon expandablebiocompatible materials. Other polymer biocompatible materials can alsobe used to fabricate these components of the device 20. In use, thedevice 20 can be folded or compacted into a delivery system anddelivered to the location of the mitral valve through transcatheterdelivery (e.g., transfemoral or transapical). Once at the location ofthe mitral valve, the device 20 can be released from the delivery systemand positioned at the mitral valve annulus area. The atrial flange 22can be placed at or on the native annulus of the mitral valve, with aportion of the atrial flange 22 extending inside the left atrium. SeeFIG. 5B. The atrial flange 22 can have a surface area that is equal orlarger than the mitral annulus area. In use, the atrial flange 22 can becovered by biocompatible polymer fabric, tissue or other biocompatiblematerials to provide a sealing effect around the device 20 and topromote tissue growth and speed up the healing effect.

The annulus support 24 functions as an anchoring feature, and caninteract with the annulus, native leaflet(s), and other internal heartstructures, or subvalvular structures, to provide the desired anchoringeffect. See FIG. 5B. In addition to the anchoring effect provided by theannulus support 24, the “clipping effect” created by the atrial flange22 and the annulus support 24 can also help the device 20 to self-alignand to resist potential migration during cardiac cycle. During therelease of the device 20 from the delivery system, the components of thedevice 20 will be released out of the delivery system in sequence. Forexample, during transapical delivery, the atrial flange 22 will bedeployed from the delivery system first, then the annulus support 24. Incontrast, during transfemoral (trans-septal) delivery, the annulussupport 24 will be deployed first, then the atrial flange 22. Theprocedures can be performed under the guidance from x-ray and/or TEE,ICE, etc.

FIGS. 4 and 5A illustrate the typical dimensional or geometry range foreach component of the device 20. The atrial flange 22 can either have acircular profile or a profile different from a full circle. Where theatrial flange 22 has a circular profile, the diameter of the atrialportion can be in the range from 20 mm to 70 mm. If the atrial flange 22has a profile which is different from full circle, the long axis can bein the range from 20-70 mm, and the shorter axis can be in the rangefrom 15-65 mm. In addition, the height H1 of the atrial flange 22 canrange from 0.5 mm to 20 mm. At the upper atrial end of the atrial flange22, each cell that defines the atrial flange 22 has peaks and valleys,with a rounded non-traumatic tip 34 at each peak thereof. The angle θ1of the atrial flange 22 in relation to the axis of the valve body 28 canbe in the range from 0 to 150 degrees. The atrial flange 22 can beeither fully or partially covered by fabric or tissue material, or acombination of tissue and fabric materials.

The valve body 28 can have a height H3 in the range from 2 mm to 30 mm.The end of the valve body 28 that is closer to the atrium side can behigher and extrude above the atrial flange 22 to reduce the length ofthe valve body 28 inside the ventricle. The cross-sectional profile ofthe valve body 28 can either be a full circular shape or a profile thatis different from a circular shape. Where the valve body 28 has a fullcircular profile, its diameter can be in the range from 15 mm to 50 mm.Where the valve body 28 has a profile which is different from a circularshape, the long axis can be in the range from 15 mm to 50 mm, and theshorter axis can be in the range from 10-45 mm. The valve body 28 canalso have a variable profile along its height. For example, the portionof the valve body 28 near the atrial flange 22 can have an oval-shapedprofile or some other profile which is different from a full circle,while the portion of the valve body 28 further away from the atrialflange 22 can have a full circular profile. The tissue leaflet(s) can beintegrated into the valve body 28 either fully in the circular portionor encompass both circular and non-circular portions. The valve body 28can be either fully or partially covered by fabric or tissue material,or a combination of tissue and fabric materials. For example, the upperportion of the valve body 28 can be covered by fabric, and the lowerportion of the valve body 28 can be covered by tissue, or vice versa. Inuse, the fabric material and tissue can either be sewn/connectedtogether first, or sewn/connected individually onto the valve body 28.The valve body 28 can be covered either along one surface (i.e.,internal or external surface), or along both surfaces (i.e., internaland external surface). At the bottom end of the valve body 28, each cellthat defines the valve body 28 has peaks and valleys, with a roundednon-traumatic tip 38 at the bottom thereof.

An optional smaller diameter neck 26 provides a transition from theatrial flange 22 to the annulus support 24. When the device 20 is in thedeployed configuration, the neck 26 extends radially inwardly from theatrial flange 22 to form a U-shaped neck 26. The cross-sectional profileof the neck 26 can either be a full circular shape or a profile that isdifferent from a circular shape. Where the neck 26 has a full circularprofile, its diameter can be in the range from 15 mm to 50 mm. Where theneck 26 has a profile which is different from a circular shape, the longaxis can be in the range from 15 mm to 50 mm, and the shorter axis canbe in the range from 10 mm to 45 mm.

The neck 26 then transitions radially outwardly to the annulus support24, which comprises a ring of U-shaped sections 29 that alternate with aring of spaced-apart inverted V-shaped tabs 30. The neck 26 actuallytransitions radially outwardly to the ring of U-shaped sections 29,which extend radially outwardly before extending radially inwardly totransition to the valve body 28. The tabs 30 extend radially outwardlyfrom the valve body 28 and have a generally perpendicular upward bend todefine a ring that encircles the neck 26. The number of tabs 30 rangesfrom 1 to 20. The cross-sectional profile of the ring of tabs 30 caneither be a full circular shape or a profile that is different from acircular shape. Where the ring of tabs 30 has a full circular profile,its diameter can be in the range from 15 mm to 70 mm. Where the ring oftabs 30 has a profile which is different from a circular shape, the longaxis can be in the range from 15 mm to 70 mm, and the shorter axis canbe in the range from 10 mm to 65 mm. The connection point of theinverted V-shape for the tabs 30 is an enlarged point 32 whose functionis to contact or press against the annulus or the native leaflet(s) ofthe mitral valve region of the heart to secure the device 20 at theannulus area, and therefore function as anchoring features. Each tab 30has a height H4 that ranges from 0.5 mm to 10 mm. The tabs 30 can beeither fully or partially covered by tissue or fabrics. For example, theenlarged point 32 can be uncovered by fabric/tissue, while the remainderof the annulus support 24 can be covered. Use of fabric can promotetissue in-growth and provide better securement of the device 20 at theannulus in addition to providing additional sealing effect to preventPerivalvular leakage (PVL).

Thus, the ring of U-shaped sections 29 has a diameter that is greaterthan the diameter of the valve body 28 and the neck 26, but less thanthe diameter of the atrial flange 22. Similarly, the ring of tabs 30 hasa diameter that is greater than the diameter of the valve body 28 andthe neck 26, but less than the diameter of the atrial flange 22. Thetabs 30 and U-shaped sections 29 can be arranged to alternate each otherin the same general ring, and can have diameters that are about the sameas each other.

Two U-shaped tails 36 can extend from the valve body 28 at the end ofthe valve body 28. Even though two tails 36 are shown, it is possible toprovide the device 20 with only one tail 36, or three or more tails 36.As best shown in FIG. 5A, each tail 36 can be formed by extending fromtwo lower tips 38 of the valve body 28 to join a U-shaped bottom, and isused to allow a suture or other string to be tied thereto so that thesuture or string can be used to adjust the position of the device 20during deployment thereof. The tails 36 can also be connected with somefeatures in the delivery system to help with (1) valve loading (i.e.,loading the valve into the delivery system sheath); and (2) valvepositioning at the annulus region of the heart. With regards to valvepositioning, the tails 36 help to adjust the position and/or the angleof the device 20 before the final release of the device 20 from thedelivery system during deployment. Another advantage to having thetail(s) 36 is that before the device 20 is completely deployed andreleased from the delivery system, the device 20 would normally alreadystart to function (partially or fully), so this gives the physician moretime to adjust the position and suspend the device 20 before it isfinally disconnected from the delivery system. The length of each tail36 can range from 5 mm to 25 mm. The tail can be shape-set and bent intoa shape, so that the tail(s) 36 can be extended away from the circularprofile defined by the valve body 28 if desired. For example, the tail36 can suspend from the distal end of the valve body 28, and bendinwardly toward the lumen of the valve body 28.

Referring to FIG. 5B, when the device 20 is deployed in use at thelocation of a native mitral valve location, the tabs 30 are deployed and“seat” at/on the annulus, with a portion of the atrial flange 22extending inside the left atrium. This interaction of the atrial flange22 (from above) and the tabs 30 (from below) provide a “clipping effect”that is effective in securing the device 20 at the desired location.When the device 20 is deployed, the U-shaped sections 29 can positionedat a location just below the annulus, to provide an additional sealingeffect. The struts/cell space in the atrium can be fully, or partially,or not covered, by fabric and/or tissue. By providing the atrial flange22 in a partially or non-covered arrangement inside the atrium, theinterference to the forward blood flow can be minimized. The tissueleaflet(s) 48 of the device 20 is/are integrated into the valve body 28to replace the function of the native mitral leaflets. As shown in FIGS.7A and 7B, the native leaflets are positioned adjacent to, and at theoutside surface of, the valve body 28.

FIGS. 6A-6B show the exemplary laser cut configuration of the device 20.The device 20 can be laser cut from metal or polymer tubing to reach theconfiguration shown in FIG. 6A. The cut structure would then go throughshape setting, micro-blasting, and electro-polishing processes toachieve the desired profile/shape, as shown in FIGS. 1-5B. The width ofeach strut 50 can range from 0.2 mm to 1.5 mm, and the thickness of eachstrut 50 can range from 0.2 mm to 0.75 mm. The length of each cell canbe in the range from 2 mm to 20 mm. The number of rings along the lengthof the device 20 can range from 2 to 20. The number of cells along thecircumference of the device 20 can range from 2 to 20. As analternative, the device 20 can also be fabricated from flat sheet, andthen rolled to the desired shape. The device 20 can be deliveredaccording to more than one delivery method. For example, a transapicaldelivery can be used where the atrial flange 22 can be deployed first,and provide tactile feedback during the delivery procedure. The annulussupport 24 (i.e., tabs 30) will be released and deployed last tocomplete the implantation of the device 20. During atransfemoral/transseptal delivery, the tabs 30 can be deployed first,and provide tactile feedback during the delivery procedure. The atrialflange 22 will be released and deployed last to complete theimplantation of the device 20. During the delivery, the tabs 30 can bebent inward (either up and inward, or down and inward) towards the valvebody 28. When the tabs 30 are released/deployed, they can expand andpress against the valve annulus or native leaflet(s).

In use, the device 20 can be compacted into a smaller profile for easydelivery and can be delivered and deployed once it reaches the targetimplant site. The compacted device profile can be less than 48 Fr, with15 Fr to 40 Fr being the typical range for such applications

FIG. 7A shows a top view of an assembled mitral valve replacement devicethat includes the leaflets 48 incorporated with the mitral device 20described above. FIG. 7B shows a bottom view of the assembly of FIG. 7A.FIGS. 7A and 7B show the leaflets 48 in an opened position, so thatblood flow from the left ventricle to the left atrium is prevented. Thecoaption area is between the leaflets 48 and the skirt defined by thedevice 20 along the internal lumen of the device 20 in the valve body28. Similarly, FIGS. 8A and 8B are top and bottom views, respectively,of the assembled mitral valve device of FIGS. 7A and 7B, showing theleaflets 48 in a closed position, so that blood can flow from the leftatrium to the left ventricle. As best shown in FIGS. 7A-8B, and also inFIGS. 9A-11, the present invention also provides a novel leafletconfiguration. The leaflets 48 have a configuration that is essentiallythe opposite of the natural leaflet configuration, such that the valveleaflets 48 open inwardly and close by expanding outwardly to contactthe inner surface of the valve body 28. The leaflets 48 are attached tothe device 20 in a manner which allows the leaflets to freely closeinward to allow forward blood flow through the valve device. The height(depth) of the tissue leaflet(s) can vary from 2-30 mm, depending on theanatomy of the heart.

The leaflet structure is best shown in FIGS. 7A-11, and this embodimentshows the use of the three leaflets 48A, 48B and 48C that have been sewntogether along three longitudinal stitch or suture lines 72, 74 and 76.The stitch lines 72, 74, 76 extend along outer edges of the leaflets48A, 48B and 48C, and also form junction lines where the leafletstructure is connected to the valve body 28. The leaflets 48A, 48B and48C are sewn along their edges to the struts 50 that make up the valvebody 28. At the top (atrial) edge of the leaflets 48A, 48B and 48C,radial stitch or suture lines 82, 84 and 86 extend from the longitudinalstitch lines 72, 74 and 76, respectively, towards a central point 88where a flat tip 60 is located. Three inner stitch or suture lines 52,54 and 56 originate from an apex 58 where the atrial edge of theleaflets 48A, 48B, 48C are crimped together to form the central flat tip60, so that the starting point of the stitch lines 52, 54, 56 are offsetfrom the stitch lines 82, 84, 86. Each stitch line 52, 54, 56 extendsfor a short distance towards the respective stitch lines 72, 74 and 76,and merge with the stitch lines 72, 74 and 76, respectively. Thisarrangement of stitch or suture lines allows the three leaflets 48A, 48Band 48C to form an umbrella-shaped configuration for its valvularstructure where the leaflets 48A, 48B, 48C will not open all the way tothe top (atrial) stitch lines 82, 84, 86 under ventricular pressure toprevent the leaflet(s) from flipping over, and to minimize leakages. Thedistance between the domed ceiling defined by the leaflets 48A, 48B, 48Cand the top (atrial) stitch lines 82, 84, 86 is between 0.25 mm and 10mm. The leaflet structure inside the device 20 can be made usingmultiple leaflets 48 (as shown and described above) or a single leaflet48. In the case of a single leaflet, the single piece of leaflet 48 canbe folded and sewn to the shapes shown in FIGS. 7A-11 above.

Thus, the novel leaflet design of the present invention uses the reverseleaflet action to regulate the blood flow between the left atrium andleft ventricle. This reverse or “umbrella-” or “balloon-like” leaflet(s)design provides better sealing/coaptation, and also improves fatigueperformance of the valve body 28 by eliminating thecontraction/squeezing force/deformation that typically acts on the valvebody 28 using a conventional leaflet design.

FIGS. 12-14 illustrate a second embodiment of a mitral valve device 20according to the present invention, which includes the addition of clips80. The device 20 in FIGS. 12-14 also have an atrial flange 22, anannulus support 24, a neck section 26 that connects the atrial flange 22to the annulus support 24, and a valve body 28 that functions as aleaflet supporting structure, all of which can be the same as thecorresponding elements in FIGS. 1-5. Each of these components is alsodefined by struts that define cells that in turn make up a cellularmatrix.

The difference between the two embodiments is the addition of a ring ofclips 80 that are provided in spaced-apart manner around the valve body28 at a location spaced vertically below the annulus support 24. Theseclips 80 are somewhat L-shaped in that each clip 80 can extendvertically from any of the struts in the valve body 28, thenhorizontally in a radial direction before terminating in a short bend atits tip. The clips 80 function to clip or hold a portion of the nativeleaflet after the device 20 has been deployed, as best shown in FIG. 15.This clipping function improves the securement of the device 20 theannulus region of the mitral valve area. The clipping effect provided bythe atrial flange 22 and the tabs 30 is also in play here, but the clips80 provide improved securement. The height H2 defines the combinedheight of the neck 26 and the annulus support 24, and can also be variedto accommodate for the clips 80, and can range from 0 mm to 10 mm.

Once the device 20 is implanted, the atrial flange 22, the valve body 28and the anchoring mechanisms (e.g., the clipping effect of the atrialflange and the tabs 30; the addition of the clips 80) built into it orcreated by the interaction of the device 20 with native leaflet(s) andother internal heart structure (or other subvalvular structures) willmaintain the device 20 in the desired position. During ventricularsystole, when the valve created by the leaflet(s) 48 and the valve body28 is closed, the pressure from the left ventricle will generate anuplifting force and trying to push the device 20 up toward the atrium.That is one of the reasons why a reliable and adequate anchoringmechanism is needed to maintain the device 20 in position after thedevice 20 is implanted. For example, during heart contraction, thetissue leaflet(s) 48 will close the valve lumen, so that the blood willbe pumped toward the aortic valve to the aorta. In the mean time, thenative leaflet(s) move up (inward) toward the outside surface of thevalve body 28 (wrap around), and try to seal/close the mitral valve toprevent PVL. The anchoring feature(s) built in the device 20 can engagethe native leaflet(s) and other internal heart structure to prevent thedevice 20 from being pushed upward. During heart relaxation, the tissueleaflet(s) 48 on the device 20 will turn to a smaller profile to allowthe blood to flow through and fill the left ventricle. The tissueleaflet(s) 48 can be operated (opened or closed) by the combined effectof blood flow, cardiac pressure, and cyclic-pulsatile movement of thesupporting structure during the cardiac cycle.

In addition to the anchoring effect of the anchoring mechanisms (annulussupport 24 and tabs 30), the pressure applied on to the valve body 28 bythe native leaflet(s) during ventricular systole can also help to keepthe device 20 from moving upward to the atrium by applying a clampingforce onto the device 20. This is a dynamic anchoring mechanism and ittakes effect only during the ventricular systole, at which stage, thedevice 20 under the highest uplifting force trying to push the device 20up toward the atrium direction. This additional dynamic anchoring effecthelps to maintain the proper position of the device 20 and reduces theanchoring force and its duration acting onto the native heart anatomy.Over time, tissue growth/healing would connect/fuse the nativeleaflet(s) onto the valve body 28.

The key advantages/novelty of the device 20 of the present inventioninclude the following:

(1) the native leaflets and other internal valvular and subvalvularstructures are preserved;

(2) the device 20 treats heart regurgitation with minimuminterference/obstruction with the function of native structures of theheart, such as the chordae tendineae, papillary muscles, left ventricle,LVOT, impingement on the aortic valve etc.;

(3) the design of the device 20 considers the natural geometry andanatomy of the heart valve with minimal modification to the native heartvalve, the profile of the annulus, surrounding structures, andsub-valvular structures;

(4) the device 20 has a design which self-conforms to the naturalcontour of the heart anatomy and the sealing portion at the annulus cancontract and expand like a normal natural annulus;

(5) the profile of the device 20 can be set to a shape that is otherthan a full circle, such as a “D”-shape, a “o”-shape, or an oval shape,to correspond to the profile of nature annulus, and the portion of thedevice 20 that contacts near the annulus can have a “V”-shaped profileto mimic the contour of nature mitral anatomy;

(6) the anchoring features on the device 20 utilize the native leafletsand other internal valvular or subvalvular structures;

(7) the device 20 can adjust its size/profile automatically to adapt tothe left ventricle size/volume change after implantation;

(8) the device 20 can have variable profiles to help create the sealingeffect during ventricular systole, and also provides a clamping effectby interaction between the native leaflet(s) to help maintain deviceposition during ventricular systole; for example, the device 20 can havea “Transition Zone” between the atrial flange 22 and value body 28. The“Transition Zone” can have a profile which is different from otherportions of the device 20. One example is that the “Transition Zone” canhave an oval-shaped profile instead of a full circular profile. There isa long axis and a short axis in the Transition Zone, the long axis canbe arranged in a direction along “commisure-to-commisure”, while theother axis is shorter than the longer axis. The oval profile in theTransition Zone can help to create an improved sealing effect at thecommisure areas. The Transition Zone could also include the neck 26 toincrease the “sealing” surface area. This also offers a dynamicanchoring effect to the device 20 and it takes effect during ventricularsystole, at which stage the uplifting force acting on the device 20 isthe highest;

(9) the device 20 has a design which uses the native leaflet(s) andchordae to provide both sealing effect and anchoring effect;

(10) the device 20 can be implanted surgically or thoughminimally-invasive procedures, such as transapical, transseptal, andtransfemoral procedures;

(11) the tails 36 at the valve body 28 allow physicians sufficient timeto adjust the valve position/angle for ideal valve performance duringdeployment; and

(12) the inner shaft inside the delivery system can be designed and madein a manner where it is movable during the valve deployment. Forexample, during delivery, once most of the device 20 isreleased/deployed from the delivery system, the leaflet(s) 48 on thedevice 20 will start to function as the heart beats. At this time, theinner shaft of the delivery system may still be inside the lumen of thedevice 20, and may affect the movement of one of the leaflets on thedevice 20. In this situation, the inner shaft in the delivery system maybe loose from the proximal handle end of the delivery system, and pulledback proximally, so that the inner shaft will not be inside the lumen ofthe device. Therefore, all leaflet(s) 48 on the device 20 can movefreely. This means that the device 20 can achieve a better valvefunction when the tails 36 are still connected with the delivery system.In other words, the fact that the leaflet(s) 48 on the device 20 arefunctioning during the deployment will give the physician more time toadjust the valve position/angle for optimal performance.

In addition to the securement mechanisms described above, adhesivebonding/interface can also be used to secure the device 20 in the nativemitral position. One example is to use biocompatible glue/adhesive toconnect/fix/secure the device 20 in the mitral position. In use, thebiocompatible adhesive/glue can be applied on the outer surfaces of thedevice 20, such as along the outer surface of the valve body 28, theatrial flange 22 or any surface of the device 20 that might contact anynative mitral structures, such as the annulus, the atrial surface aboveor on the annulus level, native leaflet(s), heart muscles, and othervalvular and/or subvalvular structure(s), to maintain the position ofthe device 20 after implantation. Bioagents can also be added into thebiocompatible adhesive/glue to promote healing and tissue growth.

The adhesive/glue can be fast reacting in nature, and form a bond withthe native mitral structure instantly upon contact with the blood. Itcan also be actuated by heat or temperature; the heat or temperature canbe generated/controlled by electrolytic heating, or FR heating, orultrasound energy, or magnetic energy, or microwave energy, or the bloodtemperature itself, or chemical reaction, through the portion or entirestructure of the device 20.

The adhesive/glue can be also be slow reacting in nature, and form abond with the native mitral structure after a period of time uponcontact with the blood. The time needed to form the bond can vary from 1second to 2 hours, from 1 second to 28 hours, etc.

The adhesive/glue can also have a controlled reaction in nature, andform a bond with the native mitral structure in a controlled manner uponcontact with the blood. One example of this concept is to apply a toplayer (or layers) of other biocompatible materials over theadhesive/glue layer/material on the device 20. The top layer(s) of theother biocompatible material can be removed or dissolved in a controlledmanner either through the use of energy, heating, chemical reaction, ormechanically, or magnetically, to ensure that the adhesive/glueunderneath the top layer can effectively form the bond with the nativemitral structure. As used herein, “controlled manner” means the timeneeded to form the bond can vary from 1 second to 48 hours.

While the description above refers to particular embodiments of thepresent invention, it will be understood that many modifications may bemade without departing from the spirit thereof. The accompanying claimsare intended to cover such modifications as would fall within the truescope and spirit of the present invention.

What is claimed is:
 1. A mitral valve replacement device adapted to bedeployed at a mitral valve position in a human heart, comprising: anatrial flange defining an atrial end of the device; a valve bodydefining a ventricular end of the device; an annulus support thatconnects the atrial flange and the valve body, the annulus supportincluding a ring of tabs extending radially therefrom, and a ring ofU-shaped sections extending radially outwardly and alternating with thetabs; wherein the atrial flange has a diameter greater than the diameterof the valve body, and the annulus support has a diameter between thatof the diameter of the atrial flange and the diameter of the valve body.2. The device of claim 1, further including a leaflet structurepositioned at the valve body.
 3. The device of claim 1, furtherincluding at least one tail extending from the ventricular end of thevalve body.
 4. The device of claim 1, further including a neckpositioned between the atrial flange and the ring of U-shaped sections.5. A mitral valve replacement device adapted to be deployed at a mitralvalve position in a human heart, comprising; an atrial flange definingan atrial end of the device; a valve body defining a ventricular end ofthe device; an annulus support that connects the atrial flange and thevalve body, the annulus support including a ring of tabs extendingradially therefrom; wherein the atrial flange has a diameter greaterthan the diameter of the valve body, and the annulus support has adiameter between that of the diameter of the atrial flange and thediameter of the valve body; and at least one clip extending from theannulus support.
 6. The device of claim 1, wherein at least a portion ofone or more of the atrial flange, the annulus support and valve body iscovered with tissue.
 7. The device of claim 1, wherein at least aportion of one or more of the atrial flange, the annulus support andvalve body is covered with fabric.
 8. The device of claim 1, wherein atleast a portion of one or more of the atrial flange, the annulus supportand valve body is covered with tissue and fabric.
 9. The device of claim8, wherein the tissue and fabric are comprised of a layer of combinedtissue and fabric.
 10. The device of claim 1, wherein at least a portionof one or more of the atrial flange, the annulus support and valve bodyis coated with a biocompatible adhesive.
 11. The device of claim 5,further including a leaflet structure positioned at the valve body. 12.The device of claim 5, further including at least one tail extendingfrom the ventricular end of the valve body.
 13. The device of claim 5,wherein the annulus support includes a ring of U-shaped sectionsextending radially outwardly and alternating with the tabs.
 14. Thedevice of claim 13, further including a neck positioned between theatrial flange and the ring of U-shaped sections.
 15. The device of claim5, wherein at least a portion of one or more of the atrial flange, theannulus support and valve body is covered with tissue.
 16. The device ofclaim 5, wherein at least a portion of one or more of the atrial flange,the annulus support and valve body is covered with fabric.
 17. Thedevice of claim 5, wherein at least a portion of one or more of theatrial flange, the annulus support and valve body is covered with tissueand fabric.
 18. The device of claim 17, wherein the tissue and fabricare comprised of a layer of combined tissue and fabric.
 19. The deviceof claim 5, wherein at least a portion of one or more of the atrialflange, the annulus support and valve body is coated with abiocompatible adhesive.